A valve comprises a coupling device having a driven member bound to the drive shaft of a flap, a driving member bound to an output shaft of an actuator, and an elastic member. The driving member comprises attachments that hooks up the elastic member to the driving member in a temporary position in which the elastic member is elastically loaded. The driven member comprises at least one release member that at least partly releases the elastic member of the attachments when the coupling device is brought to an intermediate state or the elastic member, when the coupling device is in the intermediate state, may be at least partly released from the attachments. The elastic member once released, adopts a definitive use position under the effect of relaxation of the elastic load, the coupling device then adopting the operational state.